Chris,
>I was trying to adjust and sync my carbs last night using the shop manual.
>Everything seemed to go OK and works fine while hot. This morning when
>cold, it stumbles and stammers. Back to the drawing board. Here's the
>dumbe question... Does SU = Zenith = Stromberg? If SU is not the same, are
>the principles to set them the same?
>Here's the CD 150 question. I always assumed that I must tighten the
>"needle jet housing" (The big outer nut on the bottom of the carb) until
>snug. All adjustments are made only with the "needle jet" (the screw in
>the center of the bottom of the carb). Would I ever have to adjust the
>outer nut? I got confused when I read the "How to adjust your SU carbs" at
>Team.net.
>
>Chris
>"I always seem to be messing with the fuel system"
Answer to the first question.
SU and strombergs use the same theory of opperation, and the
designs are very similar, if you exclude that the strom uses
a diaphragm for a pressure differential measurement, and the
SU uses a close running piston. Some SUs have an idle trim
circuit, which series alpine stroms do not have, although
later emmisions stroms did.
Zenith other than being the first part of "Zenith-Stromberg" carbs,
made conventional venturi type carbs on SI to early SIII, as well
as a plethora of other applications including 4bbl carbs used on
mercedes benz.
Answer to Q2.
The outer nut on the bottom of the bowl on the strom is to allow
the main jet to be centralized relative to the needle, then locked down
in its correct position. It should be well tightened after the
centralization procedure.
And yes, the only adjustment that is provided is the main mixture
screw.
Jarrid Gross
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